Ore roasting or drying furnace.



' H. M. RIDGE.

ORE ROASTING 0R DRYING FURNACE.

APPLICATION FILED OCT. 6. |913.

Patented June 15, 1915.

5 SHEETS-SHEET l.

H. M. RIDGE.

ORE ROASTNG 0B DRYING FURNACE.

APPLICATION FILED 0CT..6, |913. u 1,143,438, Patented June 15, 1915.

y l 5 SHEETS-SHEET 2r EEES ///A&

II. M. RIDGE.

ORE RQASTING 0R 'DRYING FUHNACE.

APPLICATION FILED DCT. 6 |913.

` Harrgmic e H. M. RIDGE.

ORE ROASTING 0R DRYING FURNACE.

APPLlcAnoN FILED 001.6. 1913.

5 SHEETS-SHEET 5.

STAT y HARRY MACKENZIE RIDGE, F LDNDON, ENG-LAND.

OBE ROASTING 0B DBYING FUBNAGE.

Application led October 6, 1918. l Serial No. 798,686.

f To all whom 'it may concern:

' Be it known that I,- HARRY MAcENziE RIDGE, a subject of the King of Great Britain, residing in London, England, and whose postoflice address is 62 London Wall, in the city of London, England, have invented certain new and useful Improvements Ore Roasting or Drying Furnaces, of whlch the following is a specication.

This invention relates to multiple hearth furnaces for roasting or drying crushed or finely divided ores, concentrates, slimes or the like, wherein the ore is rabbled and caused to traverse the several hearths in succession by the operation of a series of rabble arms carried by a number of suitably spaced vertical shafts which extend downward or upward through the several tiers of hearths. Y

The primary object of the present inventionis so' to construct such furnaces that,

part thereofcan be put out of operation, for the purpose "of renewals or repairs, without shutting down the entire furnace. l/Vith this object the rabbles and feed holes, and the discharge holes from the various hearths, are Aso arranged that while in normal working when the entire furnace is in operation, the ore or the like traverses the entire length of each hearth in succession but should it be desired to cut out part of the furnace the rabble shafts of that part are stopped and the ore, without other alteration than the opening or closingof one or more feed inlets or discharge outlets will, by the action of the rabble arms in operation, be caused to traverse in succession the several hearths of the other part of the furnace.

The invention is, illustrated in the accompanying drawings wherein- Figure 1 is a longitudinal section of a twoshaft three-tier roasting furnace embodying the present invention; Fig. 2 a transverse section on line 2 2 of Fig. 1, and Fig; 3 a horizontal section on line 3-3 of Fig. 1; Fig. :l is a longitudinal section of a fourf shaft three-tier roasting furnace, Figs. 5 and 6 being sections on lines 5-45, 6--6 respectively of Fig. 4; Fig. 7 is a longitudinal section of a double three-tier furnace having two parallel rows of rabble shafts; Figs. 8,/

. 9 and 10 are sections on lines 8 8, 9-9,

10 -10 respectively of Fig. 7, Fig. 11 shows in detail one of the secondary discharge openings provided in the hearths; and Fig. 12 shows in longitudinal section a furnace tures which are considered to be novel in furnaces of this class.

^ Referring first toy Figs. 1, 2 and 3 there are two rabble shafts 1, 2 vwhich extend vertically through the several hearths and are driven in opposite directions by any suitable means, each of thesek shafts having three rabble arms l, l", 1 and 2a, 2b, 2c, the former set of arms being adapted'to sweep the upper, middle andlower hearths of one half of the furnace, vand the latter set of arms the upper, ,middle and lower hearths of the other half of the furnace.

As shown in Fig. 1 the three hearths are constructed with steps or drops at the central transverse plane 'of the furnace, these steps being arranged so that there will be a drop from the left hand or feed part 3a of the upper hearth which is swept by the rabble arm 1xl and to which the ore or the like is delivered through an approximately central feed inlet c, to the righthand part #la of the upper hearth, while in :the middle hearth the drop is from the right hand part 4b of the hearth to the left hand part 3b, and in the lower hearth the:l drop is again reversed, being from the left hand part 3 to the right hand part 4c. Further, the several rabbles are designed so that they will in succession cause the ore to be traversed alternately outward from the center to the edge and inward from the edge toward the center of the successive zones or parts ofthe hearthstraversed by the ore, andthis is true whether the whole furnace sinfoperation or whether either of the rabble shafts 12 is stopped and only half the furnaceis in use. Thus, as indicated in the drawings, the-ore fed through the inlet openings c on to the feed hearth 3a is stirred by rabble arm 1a and gradually pushed outward from the center toward the ledge or step.

where it drops upon theright hand part 4a of the upper hearth and is thereworked inward by the rabble arm 2al until it reaches constructed without drops between the secl the central discharge opening e through which it drops on to the right hand part 4b of the intermediate hearth. The rabble arm 2b works the ore outward from the center of this zone until it falls over the ledge, on to the edge of the zone 3F where it is seized by the oppositely set rabbles of rabble arm 1b, by which it is worked intoward the center of the zone ldischarging through the central outlet g on to the left hand zone 3c of the lower hearth. The rabble arm sweeping this zone is designed to Work the ore outward toward the 'edge of the same so that it falls over the ledge on to zone 4c Where it is gradually swept inward by the rabble arm 2 .to the approximately central discharge opening k. In addition to the central feed inlet c there is provided a second feed inlet d so placed thatl the ore lwhen fed to the furnace through itwill fall upon the outer edge'of the zone 4*; and in addition to the various discharge openings above referred to there is a second discharge opening f in the upper hearth at or near the -periphery ofthe zone 3, a similardischarge opening h in the middle hearth at or near the periphery of the zone 4", and a discharge opening i in the lower hearth at the edge of the zone 3. One form of secondary -discharge opening is illustrated in Fig.`11. This consists of a simple opening in the brick-work covered with a loose piece of firebrick which may easily be removed and replaced from the working doors at the side of the furnace.

The various inlet and discharge openings can be closed at will, the arrangement being such that when it is desired to cut off the right hand half of the furnace, the discharge openings f, g and z' become operative so that thel ore fed in through inlet c will successively traverse the zone 38L (from center to periphery), 3b (from periphery to center) and 3c (from center to periphery); while if it is desired to shut down the left half of the furnace-the inlet d is used for feeding the ore on to the hearth zone 4a and the discharge openings e, h and k are operative, the ore traversing zones 4a (from periphery to center), 4b (from center to periphery) and 4 (from periphery to center).

It will be seen that while the central ste s or drops in the several hearths facilitate t e transference of the ore from one zone to the other, this can be effected without such drops in the hearth by means of the rabbles themselves.

There are two distinctly separate actions lthat may be performed by rabble arms,

namely, a`leveling action which spreads the ore so that it slowly but graduall moves forward when additional ore is ed onto the hearth, and a positive action which can 'be attained in various ways and especially by forming and arrangingl the rabbles so that they will impart to the ore a movement or movements in desired directions. The latter action i's-only necessary when an ore is bein treated which is only to remain in the urnace a comparatively short time. In Fig. 1, the rabble 1as.shown,`is used. for moving the ore outward from the center of the rabble path tothe periphery while rabble 2a is shown with two prongs which assist to move the ore inward from the periphery to the center of the rabble path.- In certain cases, namely where the ore is. to remain for a comparatively longtime on each lhearth and only to pass through the furnace slowly,

these prongs would not be used, and in that case all the rabbles in the furnace may be either all of the same character tending to urge the ore spirally inward or outwardv with .respect to the center of the respective rabble paths, or of kinds adapted to plow v and stir up the ore without imparting tler uc z rabbles are described and illustrated in 11S-..-

toA any .definite .direction of travel.

Letters Patent No. -1,022,961, of April 9,-

1912, enana-11,068,518, or July 29, 1913.-. Accordingly,fif fthe rabbles be all of one kind, o'r besuch as willmerely stir up the;

ore, a steady though slow progression of the ore can-bemaintained in the furnace, by reason pf such rabbles continuing to --level the ore as it is fed to the hearth and thereby causing the latter to travel slowly .from one end tothe other, and this progress ma.

be assured or expedited by giving the heart a tilt in the direction of travel in the. known manner.

In the construction of Figs. an/d 6',- thetwo intermediate rabble shafts 1 and 2 and' hearth zones 3*, 3b, 3 and 4,'4",l 4 corre-A spond with the similarly designated shafts 5 and l sweep over the same hearth zones,

and the rabble arms of shafts 6 andj2 sweep over the same hearth zones.

The construction of the various rabble arms is such, andthe inlet anddischarge openin are so situated, that when the whole inlet openings c is spread out by the rabble arms 1, 5% and subsequently traverses the upper hearth-,from left to right, the middle mace is in use the ore fed through hearth from right to left and' the lower hearth from lleft to right, the discharge oplgmgs e, g, b being operative. Y

in the case gofthe construction'shown1 middle hearth.

If it is desired to shut iowa the right half of the furnace the shafts 2 and 6 are stopped and discharge openings f, i at or near the peripheries of the zones swept by the rabble arms la, 1c are uncovered so that the ore f e d in. at inlet cis discharged fromthe feed hearth through opening f to the intermediate hearth which is traversed from 'right to left and from which it is discharged through central opening g to the lower hearth the rabble arms of which gradually work it out to the discharge opening i at the periphery. Similarly if it is desired to luse only the right half of the furnace,`

the shafts 5 and 1 are stopped and the fuel fed through inlet opening d to the center of the zone swept bythe rabble arm 2a by which it is worked gradually outward vtoward the periphery, the rabble arm 6*l acting in conjunction to drag the ore toward the central discharge opening e to the middle hearth. u The rabble arms 6", 2", together cause the ore to be traversedl along this hearth toward' the left and discharge through the peripheral opening h (uncovered for thispurpose) on -to the lower hearthalong which it gradually passes under the action of the rabbles 2, 6*" to the peripheral discharge opening b.

In the construction of Figs. 7 8, 9 and 10 the furnace is double, there being two parallel rows of rabble shafts along the length of the furnace. As shown in the drawings the rabble arms are of the kind which tend to force the ore toward the periphery of the rabbling zones, and consequently a drop or step in'each hearth is desirable in this case, in order to insure the proper progression of the ore along the hearthsor to prevent it being transferred from one half to the other of the furnace when only one of these is in operation.

Assuming the whole of the furnace to be working, the ore fed through the inlet c to the upper hearth traverses the left hand half thereof until it falls over the step ,on the central transverse section of the furnace, whereupon the rabbles on the right hand half gradually work it toward the discharge opening e, whence it falls tothe middle hearth traversing the latter from right to left and dropping through discharge hole g to the lower hearth, whence it passes to discharge opening b, the ore following the same course along the two sides of the furnace. If the four right hand shafts are stopped, the ore fed through inlet c passes downward from the upper hearth through opening f, traverses the middle hearth in the opposite opening i. Thus in this case the two additiolal discharge openings f and i are uncovere If ithe left hand half of the. furnaceI is inoperative the ore is fed through inlet d, passing along K the upper hearth from left to right, thence through discharge opening e to the middle hearth which it traverses from right toleft, dropping throughthe opening It to the lower hearth which it traverses from left to right and from which itis discharged through outlet b. f

The two sides of the double 'furnace may be quite symmetrical as shown, but whether this is so or notthe two rows of shafts are at such a distance apart that the rabbling' rabbles of any sections'can be removed or started up again without getting foul of the rabbles of the corresponding section on the side of the furnace.

In addition tothe steps or drops inthe i hearths shown on the central tranverse section of the furnace, such drops may be provided at other places, and further by providing additional, feed and discharge holes the furnace can be divided into more than four independently operative sections. For instance by the provision of auxiliary feed openings K and L and secondary discharge openings M, N, O, P, Q, the furnace may be divided into S independent sections, four on each side, a section at'each end rabbled by z the end shafts and two intermediate sections rabbled by each of the sets of three overlapping shafts.

It will be seen that in all these cases, whether the whole furnace is iii use or only a part thereof, the direction ofthe travel 0f the ore is always the same along anyv given part o f thefurnace, and consequently no change requires to be made either in the direction of rotation of the rabble shafts, or in the set of the rabbles carried by the rabble i While it is particularly desirable in the case of drying furnaces'wi-th large outputs to provide drops or steps in the hearths between the several rabbling zones so as to eX- pedite the progress of the ore or the like along the 'hearths, it is to be understood that a substantially regular, although less rapid, feed of the ore from one zone or area swept by a set of rabbles to the next zone on any given hearth can be effected without such drops or steps by having as shown in Fig. l2 the adjacent rabble shafts of the'two zones either fitted with rabbles O'f the two different lsame are operative.

characters already indicated, (that isito say the rabble arm or arms on one shaft carrying rabbles which are designedto push the ore positively outward toward the periphery of the rabbling zone and the rabbles on the other shaft designed toV deiiect-anyore coming withinA their sweep inward `tow-ard .the center of the zone, the two shafts being spaced so that the zones, do not overlap each other) or fitted with rabbles which, by spreading the ore lfed to the zone, gradually cause it. to be shifted along the hearth.l

The several rabble shafts or groups of rabble shafts are driven from separate driving shafts which are arranged to be coupled or disconnected as required, according as the whole furnace or one or more sections of the I do not claim any novelty inthe particular construction and arrangement of rabble arms here described as these are described and illustrated in the specifications ofv U. S. Patents Nos. 1,022,961 and 1,068,518, the

y novelty lying in the particular construction and arrangementl of furnace hereinbefore described inA which, however, such rabble arms may be efficiently employed to fulfil the purpose of the invention.

Having thus described the nature of vthe said invention and the best means I lmow'- of carrying the same into practical effect, -I claim e 1. In multiple hearth furnaces for roasting or drying crushedores or the like, having two or more vertical shafts carrying arms which ra'bble the ore and. cause it to traverse successive hearths in opposite directions, means whereby superimposed portions of said successive hearths and the relative rabble shaft or shafts and rabble arms ,can be put out` of action without interfering with the^working of the other part.

2. In multiple hearth furnaces for roasting or drying crushed ores or the like having two or more vertical shafts carrying arms which rabble the ore and cause it'to traverse successive hearths in opposite directions, means whereby superimposed portions of said successive hearths can be put out of action without interfering with the working of the other part comprising auxiliary closable discharge holes -in the hearths above the lowest at or near the transverse plane or planes dividing the 'separately operable portions substantially as hereinbefore described.

3. In multlple hearth furnaces for roastingzordrying crushed ores or lthe like hav# 7 ing :two or 'more vertical shafts. carrying arms which rabble the. ore and cause 1t to traverse. successive hearths in opposite directlons, means whereby one part 4'of the fur` nace can be put out of action .without interfering. with the working of the otherpart, com r1s1ng hearths constructed' with 'steps or rops on the transverse plane dividing the furnace into the sections capable of becrushed ore or the like having a plurality ofseparable rabbling zones arranged in the same plane and means for effecting progression Aof the ore from one rabbling zone to the next, substantially aslhereinbefore described.

5. A furnace for roasting or drying crushed ore or the like having a plurality of separate rab'bling zones arranged in the same plane, and a .rabble arm in each zone having rab'bles thereon adapted to spread the ore in its zone and feed it forward to the next one, substantially vas hereinbefore described.

6. In a furnace for roasting or drying crushedv ores or the like, the combination with one vertical shaft having rabble arms adapted to spread or push the ore outward toward the periphery of the zone swept by its ra'bbles, of a second vertical shaft having rabble arms adapted to deiiect or draw inwardly any ore coming within the periphery. of its zone, said shaftsbeing spaced at such a distance that the zones sweptby their respective rabble arms do not overlap, substantially as hereinbefore described. I

7. A furnace for roasting drying crushed ores or the like, consti'l'lctd. with two rows of vertical rabble shafts having ra'bble arms thereon, so arranged that the rabbling zones of each row just fail to overlap the corresponding zones of the other.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses. I

HARRY MACKENZIE RIDGE. p

Witnesses.: l

GEO. J. B. FRANKLIN,

J. W. PATGHING, 

